/* 头部区域 */
.header {
    position: absolute;
    line-height: 50px;
    padding: 0px;
    top: 0px;
    left: 0px;
    right: 0px;
    background-color: #2d3a4b;
  }
  /* 左侧导航栏 */
  .navbar {
    position: absolute;
    width: 230px;
    top: 50px;
    left: 0px;
    bottom: 0px;
    overflow-y: auto;
    background-color: #545c64;
  }
  /* 右侧主区域 */
  .main {
    position: absolute;
    top: 50px;
    left: 230px;
    right: 0px;
    bottom: 0px;
    padding: 10px;
    overflow-y: auto;
    /* background-color: red; */
  }